| BackgroundRheumatoid arthritis(RA) is a common disease which synovitis is the major pathology feature. It is a chornic autoallergic disease which can lead destruction of articular cartilage and bone. Destruction of articular cartilage and bone are the primary cause of descending of quality of life and deformity. Some researches show leptin and leptin receptor have important effect in the pathogenesy of RA. Other new investigations indicate LEP have close correlation with bone metabolism. On the one hand, LEP could produce indirectly anti-osteogenesis through hypothalamus and sympathetic nervous system, on the other hand, LEP could directly encourage bone formation and/or inhibit bone absorbtion through periphery pathway. Recent study hint LEP probably participate the regulation of production of osteoclast, influence the process of bone remodeling. So study of change of LEP and sLEP-R in RA have actually significance for understanding the osteoporosis and bone invasion in RA. It maybe supply foundational research data for the further therapy of prevention of bone invasion in the future.ObjectivesTo determine the level of LEP and sLEP-R in peripheral blood of RA and normal controls, determine the bone mineral density of all patients with RA and normal controls. Investigate the change of LEP and sLEP-R in patients with RA and the relationship between LEP or sLEP-R and osteoporosis.MethodsA total of 64 patients with RA who were diagnosed as having RA as defined by the American College of Rheumatology 1987 revised criteria were involved. Collecting blood samples of all the patients and 60 normal controls whose age and sex were matched to RA. Level of LEP and sLEP-R were measured by ELISA. BMD of non-dominant forearm, lumbar vertebrae(L1-4) and hip were measured by dual energy X-ray absorptiometry. The clinical and laboratory measurements were done simultaneously. Comparasion of level of LEP and sLEP-R between RA and normal controls were conducted. Correlations between change of LEP or sLEP-R in RA and BMD, osteoporosis were analyzed.Results1. Compared with normal controls, the level of LEP in RA increased significantly, the level of RANKL in RA decreased significantly(P<0.0001).2. BMD of all detected region such as non-dominant forearm, lumbar vertebrae(L2-4) and hip in RA were significant reduced than that in normal controls(P<0.0001). There was a higher incidence of osteoporosis in patients with RA(35.9%) than that in normal controls(15.0%)(P<0.0001).3. The level of peripheral blood LEP and sLEP-R were significant difference between RA and normal controls under different bone metabolism status(P<0.0001). The worser of bone metabolism status, the higher of LEP, the lower of sLEP-R in peripheral blood of RA. Index of joint swollen and tenderness in RA were obviously different among different bone metabolism status(P<0.05-0.01).4. Either under status of normal bone mass, or osteopenia, or osteoporosis, the level of LEP in RA was obviously higher than that in normal controls (P<0.0001), the level of sLEP-R in RA was obviously lower than that in normal controls(P<0.0001). BMD of most region in RA were obviously lower than that in normal controls(P<0.0001), especially under status of osteoporosis.5. Both in RA and in normal controls, the level of LEP and sLEP-R were same in different sex groups. Either in RA or in normal controls, compared with premenopause women, the level of LEP increased significantly in menopause women(P<0.0001), the level of sLEP-R decreased significantly in menopause women(P<0.0001). BMD of menopause women in RA were obviously lower than that of premenopause women(P<0.0001). There were no difference in BMD, incidence of osteoporosis, peripheral blood LEP and sLEP-R between patients with RA who ever used glucocorticoid or not(P<0.0001).6. There was a positive line correlation between age and level of LEP of peripheral blood in RA(P<0.0001). There were negative line correlations between BMD and level of LEP of peripheral blood in RA(P<0.05-0.001). There was a negative line correlation between age and level of sLEP-R of peripheral blood in RA(P<0.0001). There were positive line correlations between BMD and level of sLEP-R of peripheral blood in RA(P<0.05-0.001). There were no correlations between all index of clinical and laboratory such as index of joint swollen and tenderness, HAQ, WBC, HB, BPC, ESR, CRP, RF and level of LEP or sLEP-R of peripheral blood in RA(P<0.05-0.001).7. Analysis of Logistic Regression showed the level of sLEP-R in peripheral blood in RA was a independent, protective factor in occurrence of osteoporosis of RA (OR=3.089, P=0.017, CI 95%: 0.017-7.108).Conclusion1. Compared with normal controls, the level of LEP in RA increased significantly, the level of sLEP-R in RA decreased significantly. There was a higher incidence of osteoporosis in patients with RA than that in normal controls. The worser of bone metabolism status, the higher of LEP, the lower of sLEP-R in peripheral blood of RA.2. There were close correlations between age, menopause and BMD, the level of LEP, sLEP-R. There were negative line correlations between BMD and level of LEP of peripheral blood in RA. There were positive line correlations between BMD and level of sLEP-R of peripheral blood in RA. There were no correlations between clinical and laboratory index and level of LEP or sLEP-R of peripheral blood in RA.3. Increasing of sLEP-R in peripheral blood in RA was a independent, protective factor in occurrence of osteoporosis of RA. |
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